Method of making rotors



R. RUTHENBURG METHOD OF MAKING ROTOHS Sept. 14,1926.

Filed July 6, 1922 4 sheets sheet 1 Sept. 14 1926.

L. R. RUTHENBURG METHOD OF MAKING ROTORS.

4 Sheets-Sheet 2 Filed July 6. 1922 5 I'l' H 3 m w r l lll Ill 5 a 41%--F p Q v la-Ii Y Sept. 14 1926,

METHOD OF MAKING ROTQRS Filed July 6. 1922 4 sheets-sheet s PatentedSept. 14, 1926.

1,599,840 UNITED STATES PATENT QFFICE.

LOUIS R. nu'rnnnnuno, on DAYTON, OHIO, ASSIGNOB so TH-n DAYTONENGINEERING LABORATORIES COMPANY, OF DAYTON, 01110, A CORPORATION orOHIO.

METHOD O1? MAKING ROTORS.

Application filed July 6, 1922. Serial No. 573,076.

This invention relates to rotors for dynamo electric machines and, moreespecially, to motor armatures having stiff bar windings whose ends formrigid leads connecting the windings to a commutator. In constructionsand processes of manufacture used heretofore, the stiffness of the leadshas necessitated manual operations in conparticularly at high speeds. I

In the accompanying drawings:

Fig. 1 is a perspective view of a hairpin bar winding employed in theproduction of armatures according to the present invention;

Fig. 2 is a perspective view of an insulating member forming a part ofthe armature;

Fig. 3 is a side elevation of a number of bar windings, an armature coreand a plurality of insulators in assembling positions;

Fig. 4 is a top plan view thereof;

Fig. 5 is a side view of the armature parts shown in Fig. 3 in theirassembled positions Fig. 6 is a side view of a partially completedarmature with the bar winding leads grouped in pairs;

Fig. 7 is an end view of the armature shown in Fig. 6 with all thewindings assembled in the armature core;

Fig. 8 is a side view of a commutator forming a part of an armatureembody mg a the present invention;

Fig. 9 is a partial sectional view thereof taken substantially on theline 9-9 of F ig. '8; I

Fig. 10 illustrates a step in the process of assembling the commutatorwith the armature core carrying the windings;

Fig. 11 illustrates another step in the process of connecting thecommutator with the armature core and its windings;

Fig. 12 is a plan view of a tool employed in the process of assemblingthe commutator and he, bar windings;

Fig-13 is a view similar to Fig. 11 but showing the commutator in itsfinal posit-ion relative to the armature core;

Fig. 14 is a partial end view, taken on the line 14514 of Fig. 13, ofthe cominu tator and bar windings;

Fig. 15 shows the relative positions of the commutators, risers, andwinding leads after the risers have been bent over the leads;

Fig. 16 illustrates the manner of finally securing the risers to theleads;

Fig, 1.7 is a side view of a modified form of riser;

Fig. 18 is a plan view thereof;

Fig. 19 illustrates a manner of removing the projecting free ends of thewinding leads;

Fig. 20 is a side view of a completed armature; and

Fig. 21 is an end View thereof.

The hairpin bar winding illustrated in Figs. 1, 3, and 4 has parallelarms 31, 32 joined at one end by a transverse yoke 33 having an offsetportion 34 spacing the arms 31, 32 and holding the latter in difi'erentradial planes so that a plurality of Windings may be assembled in anarmature core 35 mounted on an armature shaft 36, with one arm 31 seatedin the inner portion of an armature slot 37 and the other arm 32 in theouter portion of another slot 37. The free ends 38 01' the arms arerounded and tapered. This form of hairpin bar winding is preferredbecause the portion 34 is offset transversely of the armature andprojects a minimum distance from the adjacent ends of the parallel arms31, 32, but the present invention is not limited to any specific form ofbar winding.

39 is an 8-shaped insulating tube having two longitudinal passages 10,41 separated by a transverse web 42, thewalls of the passages beingformed by the sides of the insulating tube.

When assembling these members by hand, the armature cone is laid on itsside, the free ends or leads are inserted in the slots 37 of thearmature core 35 forming a nest of windings projecting from this end ofthe armature core, and the insulating tubes 39 are inserted into theslots 37, from the opposite end of the armature core. It desired a stripof insulating material 4:3 (Fig. l) may lit} inserted bet-ween the arms31, 32 of the nested windings. The material forming the inslulatingtubes is usually relatively still and the free edge portions 39 of eachtube tend to more outwardly away from the dividing wall l2 between thechannels 4L0, and press against the walls ot the slots. hen theinsulating tubes and windings are pushed further into the slots. theleading; ends of the tubes pass over the rounded ends 38 of the barwindings. The assembling of the bar windings in the slots before theinsulating tubes are in final position atlords a relatively largeopening into which the bar ends are inserted and promott: rapid assemblyof the windings. The slot walls hold tht: bar windings a -d insulatingtubes in alignment and guide the windings into the channels on thetubes.

it is an assen ling or holding tool having a base d5 apertured at 4:6 toreceive the reduced end portion l? oi? the armature shaft 36. ?rojeetingfrom one side oi this base are two concentric cylinders 48, 4:9. Theinner cylinder i8 supports the armature core at a point within theannular series of slots 3? and the outer cylinder 4:9 contacts witlthearmature core in a circle in alignment with the annular series o'ttransverse webs -12 of the insulating tubes. This holdingtool is placedon the reduced end portion 1-7 of the armature shaft. 36 and thepartially assembled windings, armature and tool are moved into a erticalposition as shown in Fig. 8. The hairpin bar windings are then presseddownwardly into the position shown in Fig. 5, the bar windings slidingthrough the channels and 111 of the insulating tubes which are held inposi tion in the armature slots during this assembling operation by thecylinder 49 of the holding tool.

The free ends or leads 50 of the inner annular series 0t windings andthe leads 51 ot the outer annular series or windings are then bentcirciunterentially and inwardly into juxtaposed re dial position withthe leads in contact edgewise as shown in Figs. 6 and T. this bendingpreferably being performed simultaneously on all of the leads of bothseries by a bendin apparatus such as is shown in the copcndiua applicaon of Robert H. r hlers and Earl M. Poll: Fatent lIo. 1.558.891 issuedOctober 13. 1925. An insulating strip similar to the strip 43 i. placedbetween these two series oi leads shown in Fig. 7. During this bendingoperation. the leads 50 and 51 are pressed into substantially finalposition with each pair of lea ls 50 and 51 in contact and positionedlongitudinally of the armature. the stillness of the leads maintainingtheir relative positions during subsequent operations. The annulus otthe leads has a normal internal diameter approximately equal to theoutside diameter of the comu'iutator. The leads may be pressed inwardlyso that the inner surfaces out the leads 50 form a broken annularsurface smaller in diameter than the outer surface ot the commutator onwhich they are to be finally located.

The commutator 53 has a hub apertured at 55 to receive the shaft 36 ofthe armature core, on which shaft the hub is press fitted. Mounted onthe hub 54 an annular series of conunutator segment blocks 56 spaced byinsulating strips 57. The commutator segments have risers 5% which arepreferably formed of L-shape-l copper strips secured in pairs about eachscgn'ient. Each COll'lPlBiO segment comprises a segment bloci: fill anda pair of L-shaped copper strips whose longer legs :39 are held securelyagainst the sides of the segment block 56, forming a continuous segmentextending over two legs 59 and the intervening biocl: with two flexiblearms or risers 58 forming the shorter legs of the L-shaped strips.projecting radially from the segment.

Referring to Figs. 10, 11, 12, and 13, the eonmiutator is slipped overthe end 4'7 of shaft 36 and adjusted angularly to bring the slot 60between each pair of risers 58 of a commutator segment in alignment witha radially juxtaposed pair 01 leads 50. A tool 61 having a narrow slot62 at one end adapted to receive a pair of leads 50, 51. is movedradially inward over each pair ol leads to hold the atter in properlyspaced radial positions. It desired radial pressure may be applied tothe tools 61 to bend the pairs of leads 50, 51 inwardly and preset themwith the inner edges of the leads 50 within a radius of the commutatorinstead of presetting them during the bending ot the leads to juxtaposedpositions. The cornmutator is then pressed axially toward the armaturecire until the leads enter the slots 60 (see Fig. 11) the tools 61 arewithdrawn, and the coimnutator is pre d into final position on thearmature shaft 36 against the shoulder (33 formed thereon. in whichposition the rounded ends of the leads project through the slots (30(Fig. 13).

During the pressing of the commutator on the armature shalt. the roundedends (it the inner leads 5O ride over the leading end of the connnutalorforcin the two series of leads outwardly, the spring in the copper armsforming the windings and leads caus ing the inner series of leads 50 topress tightly against and form a good electrical contact with thecommutator segi'nent blocks 56. and the outer series of loads 51 topress against the inner series of loads 50.

Each pair of risers 58 is then pressed against the sides of a pair ofjuxtaposed leads 50, 51 and over the outer. edge of a lead 51 to formshoulders 64 clamped against the outer leads (Fig. 15). The commutatoris then dipped in molten solder to a point above the inner surface ofthe annular series of risers 58 and before the solder has set upon thecommutator, a tool 65 is clamped onto each pair of risers, pressing thelatter firmly against the leads 50, 51, and the solder is permitted tocool while the parts are so clamped. This squeezes out excess solder andpresses the risers into final position about the leads, the solderpreventing the risers springing away from the leads when the, clampingtool 65 is removed. This method produces good electrical contactbetweenthe risers and leads by forming the risers closely about theleads, binding the leads tightly against the segment blocks 56, andreducing to a minimum the solder between the leads and risers, whichsolder usually has a much higher resistance to flow of an electricalcurrent than the copper e1nployed in the commutator and windings.

In Figs. 17, 18 is shown a modified form of commutator in which risers66, 67 projecting outwardly from a segment block 56 have reversedcomplementarily biased ends 68, 69 clamped over the outer edge of a lead51 These riders may be preformed with their ends overlapping and theirinner surfaces closer together than the thickness of a bar winding orlead so that the forcing of the i tapered ends of the leads between therisers causes the risers to fit closely about the leads. This preformingof the leads substantially to final shape may be effected with eitherkind of riser when the latter are cut and save an operation in initiallyshaping the risers about the leads. If the slots 60 between the risersare relatively wide the aligning tool 61 need not be used, however theuse of a tool for this purpose assists in rapid assembly with risersspaced far apart and with risers preformed to substantially final shape.

The armature is then placed in a lathe having head stock 70 and tailstock 71 and rotated. A saw 72 driven by a shaft 7 3 supported by arm 74movable about an axis 75 is moved inwardly toward the axis of thearmature to cut off the ends of the leads 50 and 51, which projectthrough the risers 58. Solder deposited on the commutator seg-- mentsduring the dipping operation is then removed from the commutator and thearmature is completed.

The annular series of yokes 33 joining the bar windings 31, 32 projectsa Very small distance from the left-hand end of the armature as viewedin Fig. 20, and the leads 50 and 51 of the windings are-pressed closelytogether at the opposite end of the armature core forming a structurehaving a relatively per in the bar windings is effected over prior 7"constructions employed with armatures of the same size.

The assembling of an armature by moving the connnutator axially intoposition, assists in the saving of material by permitting a closergrouping or pressing together of the leads as shownat the right-hand endof the armature in Fig. 20 than is possible where the leads aremanipulated by hand to place them in slots cut in segment blocks. 1'

By clamping and forming the flexible risers around the leads while thesolder is plastic, substantially all of the excess solder will be forcedout so that the electrical resistance between the leads and the riserswill be reduced to the minimum. The use of relatively light weightrisers permit a substantial reduction in centrifugal force affecting thecommutator. It has been found in practice that by employing flexiblerisers to connect the commutator segments to the stiff leads, moving thecommutator axially into position between the assembled leads, andattaching these risers to the leads by machine operation as contrastedto the hand operations necessary in prior constructions, a marked savingin cost is obtained, and the armature will withstand hard usage, andcentrifugal force at high speeds better than prior forms in which thebar leads are wedged or riveted into slots cut in a projectingcommutator ring.

Armatures made according to the method above described may be rotated at20,000 R. P. M. without damage to the windings or commutator, andstarting motors employing this construction may be operated withoutusing an overrunning clutch to prevent high armature speeds when theinternalcombustion engine, started by the motor, becomes self-operativehat I claim is as follows:

1. The method of assembling a commutator upon an armature having stiffwinding leads, comprising, bending the leads substantially to theirfinal position but to a slightly closer position to the armature axisthan their final position, moving the commutator axially toward saidleads to cause the ends of said leads to enter and ride UPCJ the bottomof slots in said commutator and thereby spring said leads radiallyoutward to their final position, and then permanently securing saidleads to said commutator.

2. The method of assembling a commutal h; the ends of said leads lllitldiameter than the final reoi. then moving: the eoinniutatoi" o nos on toengage said leads and spring thezai radially outward to iiiiil position.

3. i w method of assembling a commutator upon an armature having twoseries of LlOjCPtlllQ still winding leads, comprising,

ls into lYO i nular series outer leads arranged in pairs I: 1 ehiser tothe arinature axis than finzl position, then lllOVlnflf said eadsaxially into slots on the commutator whereby said leads are spr iugradially outward to the r tin-e1 position and pressed "liflll'lji'against the bottom of said slot and tor upon an armature ha ingprojecting stiff againsteach other by the spring action of leads. eonprising. arranging the-Athe stitl' leads. th 1' final n sition exceptthat theli The method of assen'ibling a commutator upon an armaturehaving two series of projee stitl Winding leads, eoin rising hendiu 'dleads into two annular series li inner and oute leads arranged in pairsand bent slightly closer to the t :matnre axis than their lnal position,then lllOYlllfJ said leads axially into slots on the eoinn'utatorwhereby said leads are sprung radially outward to their final positionand pressed against the bottom of said slot and 2 each other by thespring action of the still leads, and then rigidly securing id eads tosaid commutator.

testin'ion whereol I hereto altix my nature.

LOUIS I. RU'IHENBURG.

